It is an article of faith among many wine lovers — and a good number of winegrowers, too — that old vines are inherently superior to younger vines when it comes to wine of the highest quality. But is that actually true?

The scientifically-minded submit that this worship of old vines has no basis in verifiable fact, which is another way of saying, “We have no instruments that can measure any differences, therefore it doesn’t exist.”

In Jamie Goode’s superb book “The Science of Wine: From Vine to Glass”, Mr. Goode quotes South African grape-growing expert Dawid Saayman, who says, “A popular notion is that very old vines with deep roots express terroir better than their younger counterparts. The claims … are based on the assumption that roots are better able to exploit the underlying geology. In turn, this is considered to contribute certain minerals and impart a certain character to the wine. There is no scientific proof for this.”

Winegrowers, for their part, can be self-serving in their anecdotal reports about the virtues of old vines. Like parents who paid a fortune in music lessons, they’re going to find virtues in the performance of their prodigy, whether any are present or not.

So, do old vines really make a difference? They do. I had some firsthand (or rather, palate) experience with this when I was living in Italy ‘s Piedmont region in 1992–93. The fall harvest weather in 1992 in Piedmont was simply awful thanks to relentless rains. It was like living in a car wash.

During the harvest I slogged by to say hello to the Currado family, who own the much-admired Vietti winery. One of Vietti’s specialties is its barbera from the Scarrone vineyard.

I found Alfredo Currado and his son, Luca, fretting about what to do with the barbera grapes from Scarrone. Their standards are exacting and the overall quality was none too promising. A small part (about 1? acres) of the Scarrone vineyard had vines that, at the time, were about 50 years old. Both father and son confirmed that these grapes had withstood the deluge better than those from the younger vines.

“Why don’t you segregate the grapes into a separate ‘Vigna Vecchia’ (old vine) bottling?” I suggested. “Of course, it will cost consumers more, but they’ll pay.”

The Currados had never before done such a thing. The market for upscale barbera was then nonexistent. But such was the woefulness of the 1992 vintage that they figured they had nothing to lose. So they made two Scarrone barberas: an old-vine version and one from younger vines. The oldvine Scarrone was dramatically, indisputably, you-can’t-miss-it superior. Today, the latest vintage of Scarrone “Vigna Vecchia” sells for $85 a bottle.

What do old vines offer? For starters, they give inherently low yields. It takes a grapevine three years before it bears its first fruit. Young vines are vigorous. From four years to 25 years, the vine has plenty of oomph and willingly offers an abundant crop if not severely pruned. This is why serious growers often perform what’s called a “green harvest,” where they scissor-off and discard excess grape clusters well before the harvest.

Like the rest of us after a certain age, older vines slow down. They are not as fecund. However, the vine roots are deep. Their grapes are fewer, as well as often more full of character. At minimum, old vines can withstand seasonal vicissitudes with greater resilience. Often their berries are smaller, more intense-tasting, and have thicker, more rain- and rot-resistant skins. The result can be — and often is — superior wine.

Can you actually taste the old vines? Not exactly. But you can taste the consequence of characterful grapes and very low yields in flavor complexity and textural density.

But what about the scientists and their insistence that this business about old vines is bosh? Well, they may know science, but they rarely know wine.

The French novelist Jean Giono put it best: “I don’t believe that one can know anything through science alone. As an instrument it is both too precise and too harsh. The world is filled with so many sorts of tenderness. To understand them, and before knowing what they represent as a whole, one must yield to them.”